According to the data from the U.S. Center for Disease Control, breast cancer is one of the commonest cancers in women, and the second leading cause of cancer death in women after lung cancer. Nowadays, breast cancer is the fifth commonest cancer. In 2012, there are approximately 522,000 patients died of breast cancer worldwide. Because of westernized diet, the female population suffered from breast cancer increases worldwide year after year, especially in East Asia. The U.S. Preventive Services Task Force recommends mammography every two years for women at the ages of 50-74.
X-ray mammography has been a common approach in early detection of breast cancer. In this approach, X-ray is emitted to penetrate the breast tissue for image generation. However, X-ray is an ionizing radiation, and therefore its dose for the subject should be in a low dose. Furthermore, the false-negative result from X-ray mammography is due to the difference of breast densities. In addition, the subject feels uncomfortable because the device for X-ray mammography lies on the breast.
In ultrasound detection, no radiation is introduced, and no adverse biological reaction occurs. Therefore, ultrasound detection is a safe way for image generation. After ultrasound is emitted from a probe to a body, it is reflected or scattered back to the probe to be received. The received ultrasound is converted to an electronic signal by a system, and then the image is provided for analysis. The reflected or scattered ultrasound is affected according to physical characteristics of the tissue, e.g. tissue density, and therefore ultrasound can be applied to various kinds of tissues, such as a cyst full of mucus or a solid tissue (a tumor tissue) in the breast. Furthermore, in X-ray mammography, both tissues appear white, but they don't do so in ultrasound detection. As above, breast ultrasound has been used in a supplemental imaging method for detection of high-density breast.
Previously, a handheld ultrasound scanner is employed for screening of breast cancer. This screening greatly depends on a sonographer, and is a labor intensive way for the detection of breast cancer. The scanning consistency varies with different patient workloads, so miss detection happens occasionally.
Accordingly, there is a need to develop a whole breast ultrasound image-capturing device which can provide automatic ultrasound imaging techniques for the whole breast.